Mountain Province is sometimes incorrectly named Mountain in some foreign references. The name is also incorrectly shortened by locals to Mt. Province, which in turn is read by native Anglophones as "Mount Province". The province was named so for being in the Cordillera Central mountain range found in the upper realms of Luzon island.

The area of the Cordillera mountains proved difficult to control by the Spaniards. From 1566 to 1665, they sent expeditions to conquer the land but the rugged terrain and hostile indigenous population at the time were major obstacles to complete subjugation.[9]

Formerly called La Montañosa by the Spanish colonizers due to its mountainous terrain,[6][10] the area was subdivided into 6 comandancias politico-militar.[11]

In August 19, 1908, during the American rule, the Philippine Commission enacted Act No. 1876, which organized the entire area of the Cordilleras into one large province, named Mountain Province.[3][5][6][12] The first governor was Samuel Cane, and the town of Bontoc was made the capital. It was originally composed of the sub-provinces of Amburayan, Apayao, Benguet, Lepanto-Bontoc, Ifugao and Kalinga.[10][5] Amburayan was later abolished in 1920 and its corresponding territories were transferred to the provinces of Ilocos Sur and La Union. Lepanto was also reduced in size and its towns were integrated into the sub-provinces of Bontoc and Benguet, and to the province of Ilocos Sur.[9][13][14]

An old map showing
the province and its original boundaries

The 6 former sub-provinces of Mountain Province under Act No. 1876 [3][11][5][14]

It has an area of 215,738 hectares (533,100 acres),[1] with 83% mountainous while 17% make up hills and levels. The province has many rivers, waterfalls, mountains, and caves. The central and western areas of the province are characterized by rugged mountains and steep cliffs, while the eastern portion has generally sloping terrain.[6][10]

As of 2010, the most populous barangay in the province is Poblacion in the municipality of Paracelis, with a total of 5,687 inhabitants. Balintaugan in the municipality of Bauko has the least population with only 144.[18]

Based on the 2000 census survey, 52% of the population are Kankana-ey. Other ethnic groups living in the province are the Balangao 13.6%, Ibontoc 12%, and other ethnicity comprise about 21.6% of the province's population.[20]

Roman Catholicism predominates in the province with approximately 60% adherence. In 2014, The Vicariate Apostolic of Bontok and Lagawe recorded a 61.5% Roman Catholic adherence. Like the neighboring province of Ifugao, the most significant religion other than Roman Catholicism is the Aglipayan Church while many people are still professing indigenous beliefs.